如何在MVC Controller中实现数据访问层 [英] How to implement a data access layer within MVC Controller

问题描述

我知道数据访问层（或简称DAL）用于访问和检索数据库中的信息，但是我不确定如何在控制器中调用DAL数据。
例如，我在DAL中创建了这个静态类，但是我不确定如何调用它给我的控制器，因此不胜感激。 DohvatiMetodu是该类的名称。

I understand that data access layer's or simply DAL's are used to access and retrieve information from a database, but i'm not sure how to call the DAL data within the controller. For instance i made this static class within my DAL but i'm not sure as to how to call it to my controller, any help or guideline would be appreciated. DohvatiMetodu is the name of the class.

public static FormInputViewModel DohvatiMetodu()
        {
            var viewModel = new FormInputViewModel();
            var metoda = new List<Metoda>();
            var metodaList = new List<SelectListItem>();

            using (var db = new ApplicationDbContext())
            {
                metoda = db.Metoda.ToList();
            }

            foreach (var metod in metoda)
            {
                metodaList.Add(new SelectListItem() {Value = metod.Id.ToString(), Text = metod.Naziv});
            }

            viewModel.KoristenaMetoda = metodaList;


            return viewModel;

推荐答案

根据用户的许多请求，我更新了代码完整的 存储库模式 逐步使用简单的CRUD方法：

As per the many request of users I have updated code with full Repository Pattern step by step With Simple CRUD Methods:

存储库模式添加了分隔符在应用程序的数据层和域层之间。

数据库工厂（IDatabaseFactory.cs） ：

public interface IDatabaseFactory : IDisposable
{
    Database_DBEntities Get();
}

数据库工厂实现（DatabaseFactory.cs）：

public class DatabaseFactory : Disposable, IDatabaseFactory
{
    private Database_DBEntities dataContext;
    public Database_DBEntities Get()
    {
        return dataContext ?? (dataContext = new Database_DBEntities());
    }

    protected override void DisposeCore()
    {
        if (dataContext != null)
            dataContext.Dispose();
    }
}

基本接口（IRepository.cs）：

public interface IRepository<T> where T : class
{
    void Add(T entity);
    void Update(T entity);
    void Detach(T entity);
    void Delete(T entity);
    T GetById(long Id);
    T GetById(string Id);
    T Get(Expression<Func<T, bool>> where);
    IEnumerable<T> GetAll();
    IEnumerable<T> GetMany(Expression<Func<T, bool>> where);
    void Commit();
}

抽象类（Repository.cs）：

 public abstract class Repository<T> : IRepository<T> where T : class
    {
        private Database_DBEntities dataContext;
        private readonly IDbSet<T> dbset;
        protected Repository(IDatabaseFactory databaseFactory)
        {
            DatabaseFactory = databaseFactory;
            dbset = DataContext.Set<T>();

        }

        /// <summary>
        /// Property for the databasefactory instance
        /// </summary>
        protected IDatabaseFactory DatabaseFactory
        {
            get;
            private set;
        }

        /// <summary>
        /// Property for the datacontext instance
        /// </summary>
        protected Database_DBEntities DataContext
        {
            get { return dataContext ?? (dataContext = DatabaseFactory.Get()); }
        }

        /// <summary>
        /// For adding entity
        /// </summary>
        /// <param name="entity"></param>
        public virtual void Add(T entity)
        {

            try
            {
                dbset.Add(entity);
                //  dbset.Attach(entity);
                dataContext.Entry(entity).State = EntityState.Added;
                int iresult = dataContext.SaveChanges();
            }
            catch (UpdateException ex)
            {

            }
            catch (DbUpdateException ex) //DbContext
            {

            }
            catch (Exception ex)
            {
                throw ex;
            }

        }

        /// <summary>
        /// For updating entity
        /// </summary>
        /// <param name="entity"></param>
        public virtual void Update(T entity)
        {
            try
            {
                // dbset.Attach(entity);
                dbset.Add(entity);
                dataContext.Entry(entity).State = EntityState.Modified;
                int iresult = dataContext.SaveChanges();
            }
            catch (UpdateException ex)
            {
                throw new ApplicationException(Database_ResourceFile.DuplicateMessage, ex);
            }
            catch (DbUpdateException ex) //DbContext
            {
                throw new ApplicationException(Database_ResourceFile.DuplicateMessage, ex);
            }
            catch (Exception ex) {
                throw ex;
            }
        }



        /// <summary>
        /// for deleting entity with class 
        /// </summary>
        /// <param name="entity"></param>
        public virtual void Delete(T entity)
        {
            dbset.Remove(entity);
            int iresult = dataContext.SaveChanges();
        }


        //To commit save changes
        public void Commit()
        {
            //still needs modification accordingly
            DataContext.SaveChanges();
        }

        /// <summary>
        /// Fetches values as per the int64 id value
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public virtual T GetById(long id)
        {
            return dbset.Find(id);
        }

        /// <summary>
        /// Fetches values as per the string id input
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public virtual T GetById(string id)
        {
            return dbset.Find(id);
        }

        /// <summary>
        /// fetches all the records 
        /// </summary>
        /// <returns></returns>
        public virtual IEnumerable<T> GetAll()
        {
            return dbset.AsNoTracking().ToList();
        }

        /// <summary>
        /// Fetches records as per the predicate condition
        /// </summary>
        /// <param name="where"></param>
        /// <returns></returns>
        public virtual IEnumerable<T> GetMany(Expression<Func<T, bool>> where)
        {
            return dbset.Where(where).ToList();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="entity"></param>
        public void Detach(T entity)
        {
            dataContext.Entry(entity).State = EntityState.Detached;
        }

        /// <summary>
        /// fetches single records as per the predicate condition
        /// </summary>
        /// <param name="where"></param>
        /// <returns></returns>
        public T Get(Expression<Func<T, bool>> where)
        {
            return dbset.Where(where).FirstOrDefault<T>();
        }

    }

现在要点是如何在控制器中访问此存储库模式的方法：

1。您有用户模型：

public partial class User
{
        public int Id { get; set; }
        public string Name { get; set; }
}

2。现在，您必须创建UserModel的存储库类

public class UserRepository : Repository<User>, IUserRepository
{
    private Database_DBEntities dataContext;

    protected IDatabaseFactory DatabaseFactory
    {
        get;
        private set;
    }

    public UserRepository(IDatabaseFactory databaseFactory)
        : base(databaseFactory)
    {
        DatabaseFactory = databaseFactory;
    }

    protected Database_DBEntities DataContext
    {
        get { return dataContext ?? (dataContext = DatabaseFactory.Get()); }
    }

  public interface IUserRepository : IRepository<User>
  { 
  }
}

3。现在，您必须使用所有CRUD方法创建UserService接口（IUserService.cs）：

public interface IUserService
 {

     #region User Details 
     List<User> GetAllUsers();
     int SaveUserDetails(User Usermodel);
     int UpdateUserDetails(User Usermodel);
     int DeleteUserDetails(int Id);
     #endregion

}

4。现在，您必须使用所有CRUD方法创建UserService接口（UserService.cs）：

public class UserService : IUserService
{
  IUserRepository _userRepository;
  public UserService() { }
  public UserService(IUserRepository userRepository)
  {
   this._userRepository = userRepository;
  }
  public List<User> GetAllUsers()
  {
      try
      {
          IEnumerable<User> liUser = _userRepository.GetAll();
          return liUser.ToList();
      }
      catch (Exception ex)
      {
          throw ex;
      }
  }
   /// <summary>
   /// Saves the User details.
   /// </summary>
   /// <param name="User">The deptmodel.</param>
   /// <returns></returns>
   public int SaveUserDetails(User Usermodel)
   {
       try
       {
           if (Usermodel != null)
           {
               _userRepository.Add(Usermodel);
               return 1;
           }
           else
               return 0;
       }
       catch
       {
           throw;
       }

   }

   /// <summary>
   /// Updates the User details.
   /// </summary>
   /// <param name="User">The deptmodel.</param>
   /// <returns></returns>
   public int UpdateUserDetails(User Usermodel)
   {
       try
       {
           if (Usermodel != null)
           {
               _userRepository.Update(Usermodel);
               return 1;
           }
           else
               return 0;
       }
       catch
       {
           throw;
       }
   }

   /// <summary>
   /// Deletes the User details.
   /// </summary>
   /// <param name="Id">The code identifier.</param>
   /// <returns></returns>
   public int DeleteUserDetails(int Id)
   {
       try
       {
           User Usermodel = _userRepository.GetById(Id);
           if (Usermodel != null)
           {
               _userRepository.Delete(Usermodel);
               return 1;
           }
           else
               return 0;
       }
       catch
       {
           throw;
       }
   }

}

5。现在，为您的存储库模式设置了全部，您可以访问用户控制器中的所有数据：

//Here is the User Controller 
public class UserProfileController : Controller
{

    IUserService _userservice;
    public CustomerProfileController(IUserService userservice)
    {
        this._userservice = userservice;
    }

    [HttpPost]
    public ActionResult GetAllUsers(int id)
    {
    User objUser=new User();

    objUser = _userservice.GetAllUsers().Where(x => x.Id == id).FirstOrDefault();

    }
}

干杯！ / strong>

Cheers !!

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